OK, so can we summarise\generalise by saying that light or moderate rain for a shortish period of time (a few minutes) probably won't cause it any bother. Obviously I realise it's not an 'underwater camera' and wouldn't leave it stood in heavy rain either. I just wanted to check that if it got a bit of a splash it wouldn't ruin it.
I don't actually leave my F5 stood in a torrent of rain either, but I know that I can use it in the rain without having to fret about getting it covered up straiht away.
By the sounds of it, the Hassies are quite tough and can be used in a variety of conditions, from hot to cold, dry to wet, but just nothing too extreme. If that's not the case, please let me know, but that is what I have summised by the replies to date.
I'd say a F5/1V/1D/D3 class body with a sealed lens (Canon L or new Nikon ones with gaskets) is more water resistant than a Hassy. However a F5 with a regular AFD lens is probably just as good, your main issue is getting water in the lens, if you wipe it before using the aperture/shutter rings you'll be ok and make sure you don't transfer water in focusing (water on extended barrel carried inside when focusing). Obviously if you're not using a prism, leaving the WLF chimney open in the rain is not very wise.
I've used my 501 in moderate (i.e. I could stay out with waterproofs without thinking "this is crap") rain with no issues, just made sure to wipe it every now and then to avoid getting standing water on it.
Overall, I'm more comfortable using the hassy in the rain as if water gets in it should still work while an electronic camera will just die. How you get the water out and avoid rust is another issue!
grit is the worst....
I just saw this on Amazon Ted http://www.amazon.co.uk/Fotodiox-Oly...3045018&sr=8-1 It looks ideal for a Hasselblad.
The Hasselblad 5xx is a "wet" camera, in the sense that it's well-lubricated.
That lubrication will protect some of the internal parts from moisture, although exposure to same is not recommended.
The cameras are not waterproof, but they're very solidly built and not delicate.
Benjiboy - a neat link, thanks. I'll consider one of those for any of my cameras I think! Thanks.
Thanks to all for the help. I think we've arrived at a fair number of views which seem to largely echo each other.
Ted part of being a photographer is knowing how to protect your equipment the only cameras I would trust to be waterproof are purpose built ones like the Nikon Nikonos http://en.wikipedia.org/wiki/Nikonos.